Produce high titer antisera to rat or monkey proteins with specificity as follows: goat anti-IgA will react with IgA, but not (by tests defined) with IgG, IgM, or other serum or exocrine fluid proteins; goat anti-a chain will react with IgA, but not with IgG, IgM, immunoglobulin light chains, or other serum or exocrine fluid proteins; goat anti-sIgA will react with IgA from serum and exocrine sources and probably with SC, but will not react with IgG, IgM, immunoglobulin light chains, or orhter colostral or salivary proteins; goat anti-IgM will react with IgM, but not with IgG, IgA, or other serum proteins; and goat anti-u chain will react with IgM, but not with IgG, IgA, immunoglobulin light chains or other serum proteins.